Method for manufacturing multilayer electronic component

ABSTRACT

At the time of pressing an electrode layer  12   a  against a surface of a green sheet  10   a  having a thickness of 3 μm or thinner to bond the electrode layer  12   a  with the surface of the green sheet  10   a , an adhesive layer  28  having a thickness of 0.02 to 0.3 μm is formed on a surface of the electrode layer  12   a  or the surface of the green sheet  10   a . It is possible to easily transfer a dry type electrode layer to the surface of the green sheet with high accuracy without breaking or deforming the green sheet.

TECHNICAL FIELD

The present invention relates to a production method of a multilayerelectronic device, such as a multilayer ceramic capacitor.

BACKGROUND ART

In recent years, along with a variety of electronic apparatuses becomingmore compact, an electronic device to be installed in an electronicapparatus has become more compact and higher in performance. Amultilayer ceramic capacitor as one of the electronic devices is alsoexpected to be more compact and higher in performance.

For pursuing a more compact multilayer ceramic capacitor having a largercapacity, there has been a strong demand for a thinner dielectric layer.Recently, a thickness of a dielectric green sheet has come to several μmor thinner.

To produce a ceramic green sheet, ceramic slurry made by ceramic powder,a binder (an acrylic based resin and a butyral resin, etc.), aplasticizer and an organic solvent (toluene, alcohol and MEK, etc.) isnormally prepared first, then, the ceramic slurry is applied to acarrier sheet, such as PET, by using the doctor blade method, etc. anddried by heating.

Also, in recent years, a production method of preparing ceramicsuspension obtained by mixing ceramic powder and a binder in a solvent,and performing 2-dimensional drawing on a film-shaped mold obtained byextrusion molding of the suspension has been studied.

A method of producing a multilayer ceramic capacitor by using theceramic green sheet explained above will be explained specifically. Aninternal electrode conductive paste including metal powder and a binderis printed to be a predetermined pattern on the ceramic green sheet anddried to form an internal electrode pattern. Next, a carrier sheet isreleased from the ceramic green sheet, a plurality of the results arestacked and cut to be a chip shape, so that a green chip is obtained.Next, after firing the green chip, an external electrode is formed, andthe multilayer ceramic capacitor is produced.

In recent years, as a use range of a multilayer ceramic capacitorincreases, a small size with a large capacity has become a demand in themarket. To respond thereto, an interlayer thickness of sheets formedwith an internal electrode has become steadily thinner each year.

However, in the case of printing the internal electrode paste on anextremely thin ceramic green sheet, there is a disadvantage that abinder component in the ceramic green sheet is dissolved or swollen dueto a solvent in the internal electrode paste. Also, there is adisadvantage that an internal electrode paste soaks in the green sheet.These disadvantages often cause a short-circuiting defect.

To eliminate the disadvantages, in the Japanese Unexamined PatentPublication Nos. 63-51616, 3-250612 and 7-312326, a dry type electrodepattern is separately prepared by forming an internal electrode patternon a supporting sheet and drying the same. An internal electrode patterntransfer method for transferring the dry type electrode pattern to asurface of each ceramic green sheet or a surface of a multilayer body ofceramic green sheets has been proposed.

In the technique disclosed in these publications, however, particularlywhen a thickness of the green sheet is thin, it is extremely difficultto bond the electrode pattern layer with a surface of a green sheet totransfer with high accuracy and a ceramic green sheet is partiallybroken in the transfer step in some cases.

Also, in the transfer method according to these conventional techniques,since a high pressure and heat are necessary to transfer the electrodepattern layer to the surface of the green sheet, the green sheet,electrode layer and supporting sheet often deform and become unable tobe used at the time of stacking, and there is a possibility of causing ashort-circuiting defect due to break of the green sheet.

Note that a method of forming an adhesive layer on a surface of theelectrode layer or green sheet is considered for easier transfer of theelectrode layer. However, when forming an adhesive layer directly on thesurface of the electrode layer or green sheet by a coating method, etc.,components of the adhesive layer soak in the electrode layer or greensheet. Therefore, a function as an adhesive layer is hard to beattained, and it is liable that a composition of the electrode layer orgreen sheet is adversely affected.

Also, the Japanese Unexamined Patent Publication No. 2001-23853discloses a production method of stacking multilayer blocks via anadhesive layer (adherence layer). However, in the method described inthis article, a thickness of the adhesive layer is thick as 0.5 to 5 μmand it is not suitable as an adhesive layer for transferring anelectrode layer to an extremely thin green sheet.

DISCLOSURE OF THE INVENTION

The present invention was made in consideration of the abovecircumstances and has as an object thereof to provide a productionmethod of a multilayer electronic device, by which even an extremelythin green sheet is not damaged or deformed and a dry type electrodelayer can be easily transferred to a surface of the green sheet withhigh accuracy at a low cost.

Another object of the present invention is to provide a productionmethod of a multilayer electronic device, by which components of anadhesive layer do not soak in an electrode layer or green sheet, asupporting sheet can be extremely easily released and a dry typeelectrode layer can be easily transferred to a surface of the greensheet with high accuracy.

The present inventors have been committed themselves to study forattaining the above objects, found that the object of the presentinvention can be attained by forming a dry adhesive layer having apredetermined thickness on a surface of an electrode layer or greensheet, and completed the present invention.

Namely, according to a first aspect of the present invention, aproduction method of a multilayer electronic device comprises the stepsof

-   -   pressing an electrode layer against a surface of a green sheet        to bond the electrode layer with the surface of the green sheet;    -   stacking the green sheets bonded with the electrode layer to        form a green chip; and    -   firing the green chip;    -   wherein    -   before pressing the electrode layer against the surface of the        green sheet, an adhesive layer having a thickness of 0.02 to 0.3        μm is formed on a surface of the electrode layer or a surface of        the green sheet.

According to a second aspect of the present invention, a productionmethod of a multilayer electronic device comprises the steps of

-   -   pressing an electrode layer against a surface of a green sheet        to bond the electrode layer with the surface of the green sheet;    -   stacking the green sheets bonded with the electrode layer to        form a green chip; and    -   firing the green chip;    -   wherein    -   before pressing the electrode layer against the surface of the        green sheet, an adhesive layer having a thinner thickness than        an average particle diameter of dielectric particles included in        the green sheet is formed on a surface of the electrode layer or        a surface of the green sheet.

Note that, in the present invention, “pressing an electrode layeragainst a surface of a green sheet” has the same meaning as “pressing agreen sheet against a surface of an electrode”.

In the production method of a multilayer electronic device according tothe first aspect and the second aspect of the present invention, anadhesive layer is formed on a surface of an electrode layer or greensheet and the electrode layer is bonded with a surface of the greensheet via the adhesive layer. By forming an adhesive layer, a highpressure and heat become unnecessary at the time of bonding theelectrode layer with a surface of the green sheet to transfer, so thatbonding at a lower pressure and lower temperature becomes possible.Accordingly, even when the green sheet is extremely thin, the greensheet is not damaged, a green sheet having an internal electrode can bepreferably stacked, and short-circuiting defect, etc. are not caused.

Note that when a thickness of the adhesive layer is too thin, athickness of the adhesive layer becomes thinner than asperity on thegreen sheet surface, and adhesiveness tends to decline remarkably.While, when a thickness of the adhesive layer is too thick, depending onthe thickness of the adhesive layer, spaces easily arise inside anelement body after sintering and capacitance tends to decline remarkablyby an amount of the volume. Also, when forming a thicker adhesive layerthan an average particle diameter of dielectric particles included inthe green sheet, depending on the thickness of the adhesive layer,spaces easily arise inside an element body after sintering andcapacitance tends to decline remarkably by an amount of the volume.

Preferably, a thickness of the green sheet is 3 μm or thinner, and athickness of the adhesive layer is ⅕ of the thickness of the green sheetor thinner. An effect of the present invention is particularly largewhen the thickness of the green sheet is 3 μm or thinner.

Preferably, the green sheet includes dielectric particles containingbarium titanate as its main component, and an average particle diameterof the dielectric particles is 0.4 μm or smaller. When the averageparticle diameter of the dielectric particles is too large, formation ofa thin green sheet tends to become difficult.

Preferably, the green sheet includes an acrylic resin and/or a butyralbased resin as a binder. When forming a thin green sheet by using abinder as such, a green sheet having sufficient strength can be formedeven if it is thin.

Preferably, the adhesive layer includes substantially the same organicpolymer material as that in a binder included in the green sheet. It isto remove the binder from the chip by binder removal processing underthe same condition when performing binder removal processing.

Preferably, the adhesive layer includes a plasticizer, and theplasticizer is at least one of phthalate ester, glycol, adipic acid andphosphoric ester. As a result of including this kind of plasticizer by apredetermined amount, preferable adhesiveness can be obtained.

Preferably, the adhesive layer includes an antistatic agent, theantistatic agent is an imidazoline based surfactant, and a weight basedadding quantity of the antistatic agent is not larger than that of theorganic polymer material. As a result of including this kind ofantistatic by a predetermined amount, preferable antistatic effect canbe obtained.

The adhesive layer may include dielectric particles, and the dielectricparticles have an average particle diameter equivalent to or smallerthan that of dielectric particles included in the green sheet and hassubstantially the same kind of dielectric composition as that includedin the green sheet. The adhesive layer becomes a part of an element bodyafter firing, so that it is preferable that substantially the same kindof dielectric particles are included as that included in the green sheetis included.

Note that since it is necessary to control a thickness of the adhesivelayer, an average particle diameter of the dielectric particles ispreferably equivalent or smaller.

Preferably, a weight based adding ratio of dielectric particles includedin the adhesive layer is lower than that of dielectric particlesincluded in the green sheet. It is to maintain preferable adhesivenessof the adhesive layer.

Preferably, processing of bonding the electrode layer with a surface ofthe green sheet and bonding another green sheet with a surface of thegreen sheet formed with the electrode layer is repeatedly performed toform a multilayer block, wherein a plurality of the green sheets arestacked via the electrode layers; and

-   -   a plurality of the multilayer blocks are stacked via the        adhesive layers to form the green chip.

Due to the stacking as above, it is possible to easily produce a greenchip, wherein, for example, 500 or more green sheets are stacked.

In the present invention, at the time of forming a multilayer block, astep of bonding an electrode layer with a surface of a green sheetwithout using an adhesive layer and bonding another green sheet with asurface of the green sheet formed with the electrode layer may berepeated to form a multilayer block. Then, a plurality of multilayerblocks may be stacked via an adhesive layer of 0.02 to 0.3 μm to form agreen chip.

In the present invention, the adhesive layer may be formed by a normalcoating method, etc., but is preferably formed by a transfer method.Preferably, the adhesive layer is formed on a surface of a supportingsheet in a releasable way first and pressed against a surface of thegreen sheet or a surface of the electrode layer to be transferred.

By not forming an adhesive layer directly on a surface of an electrodelayer or green sheet by a coating method, etc., but by forming by atransfer method, components of the adhesive layer do not soak in theelectrode layer or green sheet and an extremely thin adhesive layer canbe formed. For example, a thickness of the adhesive layer can be madethin as 0.02 to 0.3 μm or so. Even when the thickness of the adhesivelayer is thin, components of the adhesive layer do not soak in theelectrode layer or green sheet, so that it has a sufficient adhesiveforce and does not adversely affect a composition of the electrode layeror green sheet.

Preferably, the electrode layer is formed to be a predetermined patternon a surface of a supporting sheet via a release layer, a surface of therelease layer not formed with the electrode layer is formed with a blankpattern layer having-substantially the same thickness as that of theelectrode layer, and the blank pattern layer is composed ofsubstantially the same material as that of the green sheet.

By forming a blank pattern layer, a level difference on the surface dueto an electrode layer having a predetermined pattern can be eliminated.Therefore, even if a pressure is applied before firing after stacking alarge number of green sheets, an outer surface of a stacked body remainsflat, positional deviation in the plane direction of the electrode layeris not caused, moreover, green sheet is not staved in to causeshort-circuiting.

Preferably, the release layer includes substantially the same dielectricas that composing the green sheet. In that case, even if the releaselayer adheres to the surface of the electrode layer to remain, theremaining release layer does not cause any problem. It is because theremaining release layer is sufficiently thin comparing with the greensheet and includes the same dielectric as that composing the greensheet, so that it becomes a part of the dielectric layer as the greensheet if stacked with the green sheet and fired together.

Also, for example, by making an adhesive force of the adhesive layerstronger than that of the release layer and making an adhesive force ofthe release layer stronger than that of the green sheet and supportingsheet, the supporting sheet on the green sheet side can be selectivelyreleased easily.

Also, the release layer, adhesive layer, electrode layer and green sheetmay include a plasticizer with a binder resin, and the plasticizer isincluded preferably by 25 to 100 parts by weight with respect to 100parts by weight of the binder resin.

In the present invention, preferably, a content ratio of a binder withrespect to dielectrics included in the release layer is equal to orlower than that of a binder with respect to dielectrics included in thegreen sheet. Preferably, a content ratio of a release agent with respectto dielectrics included in the release layer is higher than that of therelease layer with respect to dielectrics included in the green sheet.

By attaining such a blending quantity, even in the case of an extremelythin and brittle green sheet, strength of the release layer becomesweaker than breaking strength of the green sheet. Therefore, at the timeof transferring the electrode layer, the green sheet does not break, therelease layer is partially broken or preferably released from theelectrode layer, and the electrode layer is preferably transferred tothe green sheet.

Preferably, a thickness of the release layer is thinner than that of theelectrode layer. The thickness of the release layer is set to bepreferably 60% or less and more preferably 30% or less of a thickness ofthe electrode layer. The lower limit of the release layer thickness isdetermined by a particle diameter, etc. of a dielectric material able tobe used for the release layer and is preferably 0.05 to 0.3 μm.

Preferably, a pressure at the time of bonding the electrode layer with asurface of the green sheet is 0.2 to 15 MPa. Also, the temperature atpressing is preferably 40 to 100° C. or so.

When the pressuring temperature is too low, it is liable that transferbecomes difficult, while when too high, it is liable that thermaldeformation arises on the supporting sheet and it becomes difficult totransfer an electrode layer having a predetermined pattern to a greensheet with high accuracy. Also, when a pressuring force is too small, itis liable that transfer becomes difficult, while when too large,possibility of breaking the green sheet becomes high and unfavorable.Particularly, when a thickness of the green sheet is thin, it ispreferable that the electrode layer can be bonded with a surface of thegreen sheet with a small pressuring force. Note that pressuring by apair of rolls is preferable.

In the present invention, preferably, the electrode layer is formed on asurface of the release layer by a thick film method using an electrodepaste. The thick film method is not particularly limited and a screenprinting, etc. may be mentioned. Note that the film may be formed by athin film method on the surface of the release layer. The thin filmmethod is not particularly limited and the sputtering method, the vacuumevaporation method and the CVD method, etc. may be mentioned.

When forming an electrode layer by the thin film methods, a binder andplasticizer component evaporate in vacuum and the release layer on thesurface of the first supporting sheet is damaged by sputtering particlesand evaporated particles. However, this affects to reduce the releaselayer strength, so that it is preferable for transferring the electrodelayer to the surface of the green sheet.

Note that, in the present invention, a material and a production method,etc. of the green sheet are not particularly limited, and a ceramicgreen sheet formed by the doctor blade method, die-coating method andwire bar coating method, etc. and a porous ceramic green sheet obtainedby performing 2-dimensional drawing on a film formed by extrusionmolding may be used.

Also, in the present invention, a concept of an electrode layer includesan electrode paste film to be an internal electrode layer after firing.

BRIEF DESCRIPTION OF DRAWINGS

Below, the present invention will be explained in detail based onembodiments shown in drawings, wherein:

FIG. 1 is a schematic sectional view of a multilayer ceramic capacitoraccording to an embodiment of the present invention;

FIG. 2A to FIG. 2C and FIG. 3A to FIG. 3C are sectional views of a keypart showing a transfer method of an electrode layer; and

FIG. 4A to FIG. 4C, FIG. 5A to FIG. 5C, FIG. 6A to FIG. 6C, FIG. 7 andFIG. 8 are sectional views of a key part showing a stacking method of agreen sheet bonded with an electrode layer.

BEST MODE FOR CARRYING OUT THE INVENTION

First, as an embodiment of an electronic device produced by a methodaccording to the present invention, an overall configuration of amultilayer ceramic capacitor will be explained.

As shown in FIG. 1, a multilayer ceramic capacitor 2 according to thepresent embodiment comprises a capacitor element 4, a first terminalelectrode 6 and a second terminal electrode 8. The capacitor element 4has dielectric layers 10 and internal electrode layers 12, and theinternal electrode layers 12 are alternately stacked between thedielectric layers 10. One side of the alternately stacked internalelectrode layers 12 is electrically connected to inside the firstterminal electrode 6 formed outside of a first end portion 4 a of thecapacitor element body 4. Also, the other side of the alternatelystacked internal electrode layers 12 is electrically connected to insideof the second terminal electrode 8 formed outside of a second endportion 4 b of the capacitor element body 4.

In the present embodiment, the internal electrode layer 12 is formed bytransferring an electrode layer 12 a to a ceramic green sheet 10 a asshown in FIG. 2 to FIG. 6, which will be explained later on.

A material of the dielectric layer 10 is not particularly limited andformed by a dielectric material, such as calcium titanate, strontiumtitanate and/or barium titanate. A thickness of each dielectric layer 10is not particularly limited but generally several μm to several hundredsof μm. Particularly, in the present embodiment, the layer is made thinas preferably 5 μm or thinner and more preferably 3 μm or thinner.

Also, a material of the terminal electrodes 6 and 8 is not particularlylimited and normally copper, a copper alloy, nickel and nickel alloy,etc. are normally used and silver or silver alloy with palladium, etc.can be also used. Also, a thickness of the terminal electrodes 6 and 8is not particularly limited and is normally 10 to 50 μm or so.

A shape and size of the multilayer ceramic capacitor 2 may be suitablydetermined in accordance with the use object. When the multilayerceramic capacitor 2 is rectangular parallelepiped, it is normally alength (0.6 to 5.6 mm, preferably 0.6 to 3.2 mm)×width (0.3 to 5.0 mm,preferably 0.3 to 1.6 mm)×thickness (0.1 to 1.9 mm, preferably 0.3 to1.6 mm) or so.

Next, an example of a production method of the multilayer ceramiccapacitor 2 according to the present embodiment will be explained.

(1) First, a dielectric paste is prepared to produce a ceramic greensheet to compose the dielectric layer 10 shown in FIG. 1 after firing.

The dielectric paste is normally composed of an organic solvent basedpaste obtained by kneading a dielectric material with an organicvehicle, or a water based paste.

The dielectric material may be suitably selected from a variety ofcompounds to be a composite oxide or oxide, such as carbonate, nitrate,hydroxide and organic metal compound, and mixed to be used. Thedielectric material is normally used as particles having an averageparticle diameter of 0.4 μm or smaller, preferably 0.1 to 3.0 μm or so.Note that it is preferable to use finer powder than a green sheetthickness to form an extremely thin green sheet.

The organic vehicle is obtained by dissolving a binder in an organicsolvent. The binder used for the organic vehicle is not particularlylimited and a variety of normal binders, such as ethyl cellulose,polyvinyl butyral, and an acrylic resin. Preferably, polyvinyl butyraland other butyral based resin are used.

Also, the organic solvent to be used for the organic vehicle is notparticularly limited and an organic solvent, such as terpineol, alcohol,butyl carbitol, acetone and toluene, is used. Also, the vehicle in thewater based paste is obtained by dissolving a water-soluble binder inwater. The water-soluble binder is not particularly limited andpolyvinyl alcohol, methyl cellulose, hydroxyl ethyl cellulose, awater-soluble acrylic resin, and emulsion, may be used. A content ofeach component in the dielectric paste is not particularly limited andmay be a normal content, for example, the binder by 1 to 5 wt % or soand the solvent (or water) by 10 to 50 wt % or so.

The dielectric paste may include additives selected from a variety ofdispersants, plasticizers, dielectrics, glass flits and insulators. Notethat a total content of these is preferably 10 wt % or smaller. Whenusing a butyral based resin as a binder resin, a content of aplasticizer is preferably 25 to 100 parts by weight with respect to 100parts by weight of the binder resin. When the plasticizer is too little,the green sheet tends to become brittle, while when too much, theplasticizer exudes to decline the handlability.

By using the dielectric paste, a green sheet 10 a is formed to be athickness of preferably 0.5 to 30 μm, and more preferably 0.5 to 10 μmor so on a carrier sheet 30 as a second supporting sheet as shown inFIG. 3A by the doctor blade method, etc. The green sheet 10 a is driedafter being formed on the carrier sheet 30. The drying temperature ofthe green sheet 10 a is preferably 50 to 100° C. and the drying time ispreferably 1 to 20 minutes. A thickness of the green sheet 10 a afterdrying is reduced to 5 to 25% of a thickness before drying. Thethickness of the green sheet after drying is preferably 3 μm or thinner.

(2) A carrier sheet 20 as a first supporting sheet is preparedseparately from the above carrier sheet 30 as shown in FIG. 2A, arelease layer 22 is formed thereon, an electrode layer 12 a having apredetermined pattern is formed thereon, and adjacent thereto, a blankpattern layer 24 having substantially the same thickness as that of theelectrode layer 12 a is formed on a surface of the release layer 22 notformed with the electrode layer 12 a.

As the carrier sheets 20 and 30, for example, a PET film, etc. is used,which is preferably coated with silicon, etc. to improve thereleasability. A thickness of the carrier sheets 20 and 30 is notparticularly limited and preferably 5 to 100 μm. Thicknesses of thecarrier sheets 20 and 30 may be the same or different.

The release layer 22 preferably includes the same dielectric particlesas that in the dielectrics composing the green sheet 10 a shown in FIG.3A. Also, the release layer 22 includes a binder, plasticizer andrelease agent other than the dielectric particles. A particle diameterof the dielectric particles may be the same as that of the dielectricparticles included in the green sheet, but is preferably smaller.

In the present embodiment, a thickness t2 of the release layer 22 ispreferably thinner than a thickness of the electrode layer 12 a and isset to have a thickness of preferably 60% or less, and more preferably30% or less.

The coating method of the release layer 22 is not particularly limitedbut a coating method using, for example, a wire bar coater or a diecoater is preferable because it is necessary to form it extremely thin.Note that adjustment of the thickness of the release layer can be madeby selecting a wire bar coater having a different wire diameter. Namely,to make the thickness of the release layer to be applied thinner, it canbe done by selecting one having a small wire diameter, inversely, toform it thick, one with a large wire diameter may be selected. Therelease layer 22 is dried after being applied. The drying temperature ispreferably 50 to 100° C. and the drying time is preferably 1 to 10minutes.

A binder for the release layer 22 is composed, for example, of anacrylic resin, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol,polyolefin, polyurethane, polystyrene, or an organic composed of acopolymer of these or emulsion. The binder contained in the releaselayer 22 may be the same as the binder contained in the green sheet 10 aor may be different from that, but preferably the same.

A plasticizer for the release layer 22 is not particularly limited and,for example, phthalate ester, adipic acid, phosphate ester and glycols,etc. may be mentioned. The plasticizer to be contained in the releaselayer 22 may be the same as that contained in the green sheet 10 a ormay be different from that.

A release agent for the release layer 22 is not particularly limitedand, for example, paraffin, wax and silicone oil, etc. may be mentioned.A release agent contained in the release layer 22 may be the same asthat contained in the green sheet 10 a or may be different from that.

A binder is contained in the release layer 22 by preferably 2.5 to 200parts by weight, more preferably 5 to 30 parts by weight, andparticularly preferably 8 to 30 parts by weight or so with respect to100 parts by weight of dielectric particle. Note that a content ratio ofthe binder contained in the release layer 22 is lower than that withrespect to the dielectric particles included in the green sheet 10 a andis preferably 10 to 50% or so thereof. It is to reduce releasingstrength of the release layer 22.

A plasticizer is preferably contained in the release layer 22 by 0 to200 parts by weight, preferably 20 to 200 parts by weight, and morepreferably 50 to 100 parts by weight with respect to 100 parts by weightof the binder. Note that a content ratio of the plasticizer with respectto the binder included in the release layer 22 is higher than that withrespect to the binder included in the green sheet 10 a and is preferably10 to 100% or so thereof. It is to reduce releasing strength of therelease layer 22.

A release agent is preferably contained in the release layer 22 by 0 to100 parts by weight, preferably 2 to 50 parts by weight, and morepreferably 5 to 20 parts by weight with respect to 100 parts by weightof the binder. Note that a content ratio of the release agent withrespect to the binder included in the release layer 22 is higher thanthat with respect to the binder included in the green sheet 10 a and ispreferably 10 to 400% or so thereof. It is to reduce releasing strengthof the release layer 22.

After forming the release layer 22 on the surface of the carrier sheet30, as shown in FIG. 2A, an electrode layer 12 a to compose an internalelectrode layer 12 after firing is formed to be a predetermined patternon the surface of the release layer 22. A thickness of the electrodelayer 12 a is preferably 0.1 to 2 μm, and more preferably 0.1 to 1.0 μmor so. The electrode layer 12 a may be configured by a single layer ortwo or more layers having different compositions.

The electrode layer 12 a can be formed on the surface of the releaselayer 22 by a thick film formation method, such as a printing methodusing an electrode paste, or a thin film method, such as evaporation andsputtering. When forming the electrode layer 12 a on the surface of therelease layer 22 by a screen printing method or a gravure printingmethod as a kind of thick film method, it is as follows.

First, an electrode paste is prepared. The electrode paste is fabricatedby kneading a conductive material composed of a variety of conductivemetals and alloys, or a variety of oxides, organic metal compounds orresinates, etc. to be conductive materials after firing, with an organicvehicle.

As a conductive material to be used when producing the electrode paste,Ni, a Ni alloy and a mixture of these are used. A shape of theconductive materials is not particularly limited and may be a sphericalshape and scale-like shape, etc. or a mixture of these shapes. Thosehaving an average particle diameter of the conductive material ofnormally 0.1 to 2 μm, and preferably 0.2 to 1 μm or so may be used.

An organic vehicle contains a binder and a solvent. As the binder, forexample, ethyl cellulose, an acrylic resin, polyvinyl butyral, polyvinylacetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, or acopolymer of these may be mentioned. Particularly, butyrals, such aspolyvinyl butyral, are preferable.

The binder is contained in the electrode paste by preferably 8 to 20parts by weight with respect to 100 parts by weight of the conductivematerial (metal powder). As a solvent, any of well-known ones, such asterpineol, butylcarbitol and kerosene, may be used. A content of thesolvent is preferably 20 to 55 wt % or so with respect to the entirepaste.

To improve the adhesiveness, the electrode paste preferably contains aplasticizer. As a plasticizer, benzylbutyl phthalate (BBP) and otherphthalate esters, adipic acids, phosphoric esters, and glycols, etc. maybe mentioned. The plasticizer in the electrode paste is preferably 10 to300 parts by weight, and more preferably 10 to 200 parts by weight withrespect to 100 parts by weight of the binder. Note that when an addingquantity of the plasticizer or adhesive is too large, it is liable thatstrength of the electrode layer 12 a remarkably declines. Also, toimprove transferability of the electrode layer 12 a, it is preferable toimprove adhesiveness and/or adherence of the electrode paste by adding aplasticizer and/or adhesive to the electrode paste.

After or before forming the electrode paste layer having a predeterminedpattern on the surface of the release layer 22 by a printing method, ablank pattern layer 24 is formed to be substantially the same thicknessas that of the electrode layer 12 a on the surface of the release layer22 not formed with the electrode layer 12 a. The blank pattern layer 24is composed of the same material as that of the green sheet 10 a shownin FIG. 3A and formed by the same method. The electrode layer 12 a andthe blank pattern layer 24 are dried in accordance with need. The dryingtemperature is not particularly limited, but is preferably 70 to 120°C., and the drying time is preferably 5 to 15 minutes.

(3) As shown in FIG. 2A, an adhesive layer transfer sheet formed with anadhesive layer 28 is prepared on the surface of a carrier sheet 26 as athird supporting sheet separately from the carrier sheets 20 and 30explained above. The carrier sheet 26 is formed by the same sheet asthat of the carrier sheets 20 and 30.

A composition of the adhesive layer 28 is the same as that of therelease layer 22 except for not containing a release agent. Namely, theadhesive layer 28 contains a binder and a plasticizer. The adhesivelayer 28 may contain the same dielectric particle as that of thedielectrics composing the green sheet 10 a, however, in the case offorming an adhesive layer having a thinner thickness than a particlediameter of the dielectric particles, it is better not to containdielectric particles. Also, when dielectric particles are contained inthe adhesive layer 28, a particle diameter of the dielectric particlesis preferably smaller than the particle diameter of the dielectricparticles contained in the green sheet.

A plasticizer is preferably contained in the adhesive layer 28 by 0 to200 parts by weight, preferably 20 to 200 parts by weight, and morepreferably 50 to 100 parts by weight with respect to 100 parts by weightof the binder.

The adhesive layer 28 further contains an antistatic agent, and theantistatic agent includes one of imidazoline based surfactants, and aweight based adding quantity of the antistatic agent is preferably notlarger than that of the binder (organic polymer material). Namely, theantistatic agent is preferably contained in the adhesive layer 28 by 0to 200 parts by weight, preferably 20 to 200 parts by weight, and morepreferably 50 to 100 parts by weight with respect to 100 parts by weightof the binder.

A thickness of the adhesive layer 28 is preferably 0.02 to 0.3 μm or so,more preferably, thinner than an average particle diameter of dielectricparticles contained in the green sheet. Also, a thickness of theadhesive layer 28 is preferably ⅕ or of a thickness of the green sheet10 a or thinner.

When a thickness of the adhesive layer 28 is too thin, the adhesiveforce declines, while when too thick, spaces are easily formed inside anelement body after sintering depending on the thickness of the adhesivelayer, and a capacitance by an amount of the volume tends to decreaseremarkably.

The adhesive layer 28 is formed on the surface of the carrier sheet 26as a third supporting sheet, for example, by a bar coater method, diecoater method, reverse coater method, dip coater method and kiss coatermethod, etc. and dried in accordance with need. The drying temperatureis not particularly limited, but is preferably the room temperature to80° C., and the drying time is preferably 1 to 5 minutes.

(4) To form the adhesive layer on the surface of the electrode layer 12a and the blank pattern layer 24 shown in FIG. 2A, a transfer method isapplied in the present embodiment. Namely, as shown in FIG. 2B, theadhesive layer 28 of the carrier sheet 26 is pressed against the surfaceof the electrode layer 12 a and the blank pattern layer 24, heated andpressed, then, the carrier sheet 26 is removed. Consequently, as shownin FIG. 2C, the adhesive layer 28 is transferred to the surface of theelectrode layer 12 a and the blank pattern layer 24. Note that transferof the adhesive layer 28 may be performed on the surface of the greensheet 10 a shown in FIG. 3A.

The heating temperature at transferring is preferably 40 to 100° C., andthe pressing force is preferably 0.2 to 15 MPa. Pressing may beperformed by a press or a calendar roll, but is preferably performed bya pair of rolls.

After that, the electrode layer 12 a is bonded with the surface of thegreen sheet 10 a formed on the surface of the carrier sheet 30 shown inFIG. 3A. For that purpose, as shown in FIG. 3B, the electrode layer 12 aand the blank pattern layer 24 of the carrier sheet 20 are pressedagainst the surface of the green sheet 10 a together with the carriersheet 20 via the adhesive layer 28, heated and pressed. As a result, asshown in FIG. 3C, the electrode layer 12 a and the blank pattern layer24 are transferred to the surface of the green sheet 10 a. Note thatsince the carrier sheet 30 on the green sheet side is peeled off, whenseeing from the green sheet 10 a side, the green sheet 10 a istransferred to the electrode layer 12 a and the blank pattern layer 24via the adhesive layer 28.

Heating and pressing at the time of transferring may be pressing andheating by a press or by a calendar roll, but is preferably performed bya pair of rolls. The heating temperature and the pressing force are sameas those at the time of transferring the adhesive layer 28.

A single-layer electrode layer 12 a having a predetermined pattern isformed on the single green sheet 10 a by steps shown in FIG. 2A to FIG.3C. A green sheet 10 a formed with the electrode layer 12 a is stacked,for example, by repeating the steps shown in FIG. 4A to FIG. 6C. Notethat, in FIG. 4A to FIG. 6C, the same reference numbers are given tocommon members with those shown in FIG. 3A to FIG. 4C, and anexplanation thereon is partially omitted.

First, as shown in FIG. 4A to FIG. 4C, the adhesive layer 28 istransferred to the surface on the other side of the electrode layer(back side) on the green sheet 10 a. After that, as shown in FIG. 5A toFIG. 5C, the electrode layer 12 a and the blank pattern layer 24 aretransferred to the back side of the green sheet 10 a via the adhesivelayer 28.

Next, as shown in FIG. 6A to FIG. 6C, on the surface of the electrodelayer 12 a and the blank pattern layer 24, the green sheet 10 a istransferred via the adhesive layer 28. After that, by repeating thetransfer, a multilayer block, wherein a large number of electrode layers12 a and the green sheet 10 a are alternately stacked as shown in FIG.7, is obtained.

Note that, without applying the steps shown in FIG. 5C to FIG. 6C, fromthe step shown in FIG. 5B, the carrier sheet on the upper side may beremoved instead of removing the carrier sheet 20 on the lower side and amultilayer unit U1 shown in FIG. 4C may be stacked thereon. After that,by repeating an operation of removing the carrier sheet 20 on the upperside again, stacking thereon the multilayer unit U1 shown in FIG. 4C,and removing the carrier sheet 20 on the upper side, a multilayer block,wherein a large number of electrode layers 12 a and the green sheet 10 aare alternately stacked as shown in FIG. 7, is obtained. A method ofstacking the multilayer unit U1 shown in FIG. 4C is superior in terms ofan efficiency of the stacking operation.

When the number of stacking layers of the green sheet is small, a firingstep in the next step is performed on the multilayer block alone. Also,in accordance with need, a plurality of multilayer blocks as such may bestacked via adhesive layers 28 formed by a transfer method in the sameway as above to obtain a multilayer body having larger number of layers.

(5) After that, as shown in FIG. 8, a green sheet 40 for an outer layer(a thick multilayer body obtained by stacking a plurality of greensheets not formed with an electrode layer) is stacked on the lowersurface of the stacked body and the entire stacked body is supported byan absorption holder 50. After that, the carrier sheet 20 on the upperside is peeled off, the outer layer green sheet 40 is formed on top ofthe multilayer body in the same way, and final pressing is performed.

Pressure at the time of the final pressing is preferably 10 to 200 MPa.The heating temperature is preferably 40 to 100° C. After that, themultilayer body is cut to be a predetermined size to form green chips.The green chips are subjected to binder removal processing and firingprocessing, then, thermal treatment is performed in order to re-oxidizethe dielectric layer.

The binder removal processing may be performed under a normal condition,but when using a base metal, such as Ni and a Ni alloy, as a conductivematerial of the internal electrode layer, it is preferably performedunder the specific condition below.

-   -   temperature rising rate: 5 to 300° C./hour, particularly 10 to        50° C./hour    -   holding temperature: 200 to 400° C., particularly 250 to 350° C.    -   holding time: 0.5 to 20 hours, particularly 1 to 10 hours    -   atmosphere: a wet mixed gas of N₂ and H₂

A firing condition is preferably as below.

-   -   temperature rising rate: 50 to 500° C./hour, particularly 200 to        300° C./hour    -   holding temperature: 1100 to 1300° C., particularly 1150 to        1250° C.    -   holding time: 0.5 to 8 hours, particularly 1 to 3 hours    -   cooling rate: 50 to 500° C./hour, particularly 200 to 300°        C./hour    -   atmosphere gas: a wet mixed gas of N₂ and H₂, etc.

Note that oxygen partial pressure in an atmosphere in the air at firingis preferably 10⁻² Pa or lower, particularly 10⁻² to 10⁻⁸ Pa. Whenexceeding the above ranges, the internal electrode layer tends tooxidize, while when the oxygen partial pressure is too low, abnormalsintering is caused in an electrode material of the internal electrodelayer to be broken.

The thermal treatment after performing such firing is preferablyperformed with a holding temperature or highest temperature of 1000° C.or higher, more preferably 1000 to 1100° C. When the holding temperatureor the highest temperature at the time of the thermal treatment is lowerthan the above ranges, it is liable that oxidization of the dielectricmaterial is insufficient to make the insulation resistance lifetimeshort, while when exceeding the above ranges, Ni in the internalelectrode oxidizes and the capacity decreases, moreover, Ni reacts witha dielectric base and the lifetime also tends to become short. Theoxygen partial pressure at the time of thermal treatment is higher thanthat in a reducing atmosphere at the time of firing, preferably 10⁻³ Pato 1 Pa, and more preferably 10⁻² Pa to 1 Pa. When it is lower than theabove range, re-oxidization of the dielectric layer 2 becomes difficult,while when exceeding the above ranges, the internal electrode layer 3tends to oxidize. Other condition of the thermal treatment is preferablyas below.

-   -   holding time: 0 to 6 hours, particularly 2 to 5 hours    -   cooling rate: 50 to 500° C./hour, particularly 100 to 300°        C./hour    -   atmosphere gas: wet N₂ gas, etc.

Note that to wet a N₂ gas or a mixed gas, etc., for example, a wetter,etc. may be used. In this case, the water temperature is preferably 0 to75° C. or so. Also, the binder removal processing, firing and thermaltreatment may be performed continuously or separately. When performingcontinuously, the atmosphere is changed without cooling after the binderremoval processing, continuously, the temperature is raised to theholding temperature at firing to perform firing. Next, it is cooled andthe thermal treatment is preferably performed by changing the atmospherewhen the temperature reaches to the holding temperature of the thermaltreatment. On the other hand, when performing them separately, afterraising the temperature to the holding temperature at the binder removalprocessing in an atmosphere of a N₂ gas or a wet N₂ gas, the atmosphereis changed, and the temperature is furthermore raised. After that, aftercooling the temperature to the holding temperature at the thermaltreatment, it is preferable that the cooling continues by changing theatmosphere again to a N₂ gas or a wet N₂ gas. Also, in the thermaltreatment, after raising the temperature to the holding temperatureunder the N₂ gas atmosphere, the atmosphere may be changed, or theentire process of the thermal processing may be in a wet N₂ gasatmosphere.

The thus obtained sintered body (element body 4) is subjected to endsurface polishing, for example, by barrel polishing and sand-blast,etc., then, a terminal electrode paste is burnt to form terminalelectrodes 6 and 8. For example, a firing condition of the terminalelectrode paste is preferably in a wet mixed gas of N₂ and H₂ at 600 to800° C. for 10 minutes to 1 hour or so. In accordance with need,plating, etc. is performed on the terminal electrodes 6 and 8 to form apad layer. Note that the terminal electrode paste may be fabricated inthe same way as the electrode paste explained above.

A multilayer ceramic capacitor of the present invention produced asabove is mounted on a print substrate, etc. by soldering, etc. and usedfor a variety of electronic equipments, etc.

In a method of producing a multilayer ceramic capacitor according to thepresent embodiment, it is possible to easily transfer a dry typeelectrode layer 12 a to a surface of the green sheet 10 a with highaccuracy without breaking or deforming the green sheet 10 a.

Particularly, in the production method of the present embodiment, theadhesive layer 28 is formed on the surface of the electrode layer orgreen sheet by the transfer method, and the electrode layer 12 a isbonded with the surface of the green sheet 10 a via the adhesive layer28. By forming the adhesive layer 28, a high pressure and heat becomeunnecessary at the time of bonding the electrode layer 12 a to transferto the surface of the green sheet 10 a, so that bonding at a lowerpressure and lower temperature becomes possible. Accordingly, even inthe case of an extremely thin green sheet 10 a, the green sheet 10 a isnot broken, the electrode layers 12 a and green sheets 10 a can bepreferably stacked, and short-circuiting defect, etc. are not caused.

Also, for example, by making an adhesive force of the adhesive layer 28stronger than that of the release layer 22 and making an adhesive forceof the release layer 22 stronger than that between the green sheet 10 aand the carrier sheet 30, etc., the carrier sheet 30 on the green sheet10 a side can be selectively released easily.

Furthermore, in the present embodiment, the adhesive layer 28 is notdirectly formed on a surface of the electrode layer 12 a or green sheet10 a by a coating method, etc. and formed by a transfer method, so thatcomponents of the adhesive layer 28 do not soak in the electrode layer12 a or green sheet 10 a, and it becomes possible to form an extremelythin adhesive layer 28. For example, a thickness of the adhesive layer28 can be made thin as 0.02 to 0.3 μm or so. Although the thickness ofthe adhesive layer 28 is thin, components of the adhesive layer 28 donot soak in the electrode layer 12 a and green sheet 10 a, the adhesiveforce is sufficient and a composition of the electrode layer 12 a orgreen sheet 10 a is not adversely affected.

Note that the present invention is not limited to the above embodimentsand may be variously modified within the scope of the present invention.

For example, in another embodiment of the present invention, as shown inFIG. 4C, after forming a multilayer unit U1 made by the green sheet 10a, adhesive layer 28, electrode layer 12 a and blank pattern layer 24, aplurality of the multilayer units U1 may be stacked and subjected topress molding by a mold, etc. to obtain a multilayer block, and themultilayer blocks may be furthermore stacked via the adhesive layer 28to obtain a green chip. Note that when obtaining a multilayer block bystacking a plurality of multilayer units U1 shown in FIG. 4C andperforming press molding by a mold, etc., the stacking may be attainedwithout using the adhesive layer 28. Note that when stacking themultilayer blocks, it is preferable to use the adhesive layer 28.

Also, the method of the present invention is not limited to theproduction method of the multilayer ceramic capacitor but can be appliedas a production method of other multilayer electronic device.

EXAMPLES

Below, the present invention will be explained based on further detailedexamples, but the present invention is not limited to the examples.

Example 1

First, each paste below was prepared.

Green Sheet Paste (as same as Blank Pattern Paste)

Powders selected from BaTiO₃ powder (BT-02 made by Sakai ChemicalIndustry Co., Ltd.), MgCO₃, MnCO₃, (Ba_(0.6)Ca_(0.4))SiO₃ and rareearths (Gd₂O₃, Tb₄O₇, Dy₂O₃, Ho₂O₃, Er₂O₃, Tm₂O₃, Yb₂O₃, Lu₂O₃, andY₂O₃) were wet mixed by a ball mill for 16 hours and dried to obtain adielectric material. An average particle diameter of the materialpowders was 0.1 to 1 μm.

(Ba_(0.6)Ca_(0.4))SiO₃ was produced by wet mixing BaCO₃, CaCO₃ and SiO₂by a ball mill for 16 hours, dried and fired at 1150° C. in the air, andwet grinding the result for 100 hours by a ball mill.

To make the dielectric material paste, an organic vehicle was added tothe dielectric material and mixed by a ball mill and a dielectric greensheet paste was obtained. The organic vehicle has a blending ratio of 6parts by weight of a polyvinyl butyral resin (PVB) as a binder, 3 partsby weight of bis(2-ethylhexyl) phthalate (DOP), 55 parts by weight ofethanol and 10 parts by weight of toluene as a plasticizer, and 0.5 partby weight of paraffin as a release agent with respect to 100 parts byweight of the dielectric material. Note that a content of DOP as aplasticizer becomes 50 parts by weight (PHR) when assuming that PVD is100 parts by weight. Also, since PVB is 6 parts by weight with respectto 100 parts by weight of the dielectric material, so that it isincluded at a rate of 6 PHP.

Release Layer Paste

A release layer paste was obtained by diluting the above dielectricgreen sheet paste by ethanol/toluene (55/10) with 4 times.

Adhesive Layer Paste

As an adhesive layer paste, an organic vehicle was used. The organicvehicle was obtained by diluting a material having a blending ratio of50 parts by weight (50 PHR) of bis(2-hethylhexyl) phthalate DOP, 1050parts by weight of ethanol, 300 parts by weight of toluene as aplasticizer, and 10 parts by weight of paraffin as a release agent withrespect to 100 parts by weight of a polyvinyl butyral resin with 5 timesby a mixed solvent of 350 parts by weight of ethanol and 100 parts byweight of toluene.

Internal Electrode Paste (Electrode Layer Paste to be Transferred)

Next, an internal electrode paste was obtained by kneading a materialhaving the blending ratio below by a three-roll to make slurry. Namely,100 parts by weight of Ni particles having an average particle diameterof 0.4 μm were added with 40 parts by weight of an organic vehicle(obtained by dissolving 8 parts by weight of an ethyl cellulose resin asa binder in 92 parts by weight of terpineol) and 10 parts by weight ofterpineol, and kneaded by a three-roll and made to be slurry, so that aninternal electrode paste was obtained.

Formation of Green Sheet and Transfer of Adhesive Layer and ElectrodeLayer

First, by using the above-dielectric green sheet paste, a green sheethaving a thickness of 0.1.0 μm was formed on a PET film (secondsupporting sheet) by using a wire bar coater. Next, the above releaselayer paste was applied to another PET film (first supporting sheet) bya wire bar coater and dried to form a release layer of 0.2 μm.

On the surface of the release layer, an electrode layer 12 a and a blankpattern layer 24 were formed. The electrode layer 12 a was formed to bea thickness of 1.2 μm by the printing method using the above internalelectrode paste. The blank pattern layer 24 was formed to be a thicknessof 1.2 μm by the printing method using the above dielectric green sheetpaste.

Also, an adhesive layer 28 was formed on another PET film (thirdsupporting sheet). The adhesive layer 28 was formed to be a thickness of0.1 μm by using the above adhesive layer paste by a wire bar coater.

First, on the surface of the electrode layer 12 a and the blank patternlayer 24, the adhesive layer 28 was transferred by the method shown inFIG. 2. At the time of transferring, a pair of rolls were used, thepressing force was 1 MPa and the temperature was 80° C. It was confirmedthat the transfer was preferably performed.

Next, by the method shown in FIG. 3, the internal electrode layer 12 aand the blank pattern layer 24 were bonded with (transferred to) thesurface of the green sheet 10 a via the adhesive layer 28. At the timeof transferring, a pair of rolls were used, the pressing force was 1 MPaand the temperature was 80° C. It was confirmed that the transfer waspreferably performed.

Next, by the method shown in FIG. 4 to FIG. 6, the internal electrodelayers 12 a and green sheets 10 a were successively stacked and stackingof 5 internal electrode layers 12 a was performed finally to obtain asample of a multilayer block.

Transferring was performed respectively on 20 same samples, and a ratio(good product rate) of those without any cracks and pinholes on thetransferred electrode layer and breaking on the green sheet wasmeasured. 95% or higher was determined @, 60 to 95% was determined o,and 60% or lower was determined x. Also, binder removal processing andfiring under a normal condition were performed on other same 20 samples,and existence of delamination was observed on sectional surfaces of therespective samples after firing by using an optical microscope and SEM.Namely, a ratio (good product rate) of those with no delaminationobserved was measured on the 20 samples, and 95% or higher wasdetermined @, 60 to 95% was determined o and 60% or lower was determinedx. The results are shown in Table 1. TABLE 1 Adhesive Layer CommonMaterial Green Sheet Plasticizer Powder Adhesive Binder Adding ParticleAdding Layer Adding Quantity Antistatic Diameter Quantity ThicknessQuantity No. Binder Kind (PHR) agent (μm) (PHR) (μm) Kind (PHR) Example1 PVB DOP 50 — None None 0.1 PVB 6 Example 2 ↑ ↑ ↑ — ↑ ↑ 0.01 ↑ ↑Example 2 ↑ ↑ ↑ — ↑ ↑ 0.02 ↑ ↑ Example 2 ↑ ↑ ↑ — ↑ ↑ 0.1 ↑ ↑ Example 2 ↑↑ ↑ — ↑ ↑ 0.2 ↑ ↑ Example 2 ↑ ↑ ↑ — ↑ ↑ 0.3 ↑ ↑ Example 2 ↑ ↑ ↑ — ↑ ↑0.5 ↑ ↑ Example 2 ↑ ↑ ↑ — ↑ ↑ 1 ↑ ↑ Example 3 ↑ ↑ ↑ — ↑ ↑ 0.1 ↑ ↑Example 3 ↑ ↑ ↑ — ↑ ↑ 0.2 ↑ ↑ Example 3 ↑ ↑ ↑ — ↑ ↑ 0.4 ↑ ↑ Example 3 ↑↑ ↑ — ↑ ↑ 0.3 ↑ ↑ Example 3 ↑ ↑ ↑ — ↑ ↑ 0.6 ↑ ↑ Example 3 ↑ ↑ ↑ — ↑ ↑0.6 ↑ ↑ Example 3 ↑ ↑ ↑ — ↑ ↑ 1 ↑ ↑ Example 3 ↑ ↑ ↑ — ↑ ↑ 2 ↑ ↑Comparative ↑ ↑ ↑ — ↑ ↑ — ↑ ↑ Example 1 Comparative ↑ ↑ ↑ — ↑ ↑ — ↑ ↑Example 2 Example 4 ↑ ↑ ↑ — ↑ ↑ 0.1 ↑ ↑ Example 4 ↑ ↑ ↑ — ↑ ↑ 0.1 ↑ ↑Example 5 Acryl DOP ↑ — ↑ ↑ 0.1 ↑ ↑ Example 5 Acryl BBP ↑ — ↑ ↑ 0.1 ↑ ↑Example 5 Acryl DOP ↑ — ↑ ↑ 0.1 Acryl ↑ Example 5 Acryl BBP ↑ — ↑ ↑ 0.1Acryl ↑ Example 6 PVB BBP ↑ — ↑ ↑ 0.1 PVB ↑ Example 6 ↑ DOA ↑ — ↑ ↑ 0.1↑ ↑ Example 6 ↑ BPBG ↑ — ↑ ↑ 0.1 ↑ ↑ Example 6 ↑ TBP ↑ — ↑ ↑ 0.1 ↑ ↑Adhesive Green Sheet Layer/ Adhesive Plasticizer Dielectric DielectricLayer/ Adding Sheet Particle Particle Sheet Quantity Thickness DiameterTransfer- Delam- Diameter Thickness No. Kind (PHR) (μm) (μm) abilityination (1 or thinner) (0.2 or thinner) Example 1 DOP 50 1 0.2 ◯ ◯ 0.50.100 Example 2 ↑ ↑ 1.5 0.4 X — 0.025 0.007 Example 2 ↑ ↑ 1.5 0.4 ◯ ◯0.05 0.013 Example 2 ↑ ↑ 1.5 0.4 ⊚ ⊚ 0.25 0.067 Example 2 ↑ ↑ 1.5 0.4 ⊚⊚ 0.5 0.133 Example 2 ↑ ↑ 1.5 0.4 ◯ ◯ 0.75 0.200 Example 2 ↑ ↑ 1.5 0.4 ◯X 1.25 0.333 Example 2 ↑ ↑ 1.5 0.4 ◯ X 2.5 0.667 Example 3 ↑ ↑ 1 0.2 ◯ ◯0.5 0.100 Example 3 ↑ ↑ 1 0.2 ◯ ◯ 1 0.200 Example 3 ↑ ↑ 1 0.2 ◯ X 20.400 Example 3 ↑ ↑ 3 0.4 ◯ ◯ 0.75 0.100 Example 3 ↑ ↑ 3 0.4 ◯ X 1.50.200 Example 3 ↑ ↑ 4 0.8 ◯ ◯ 0.75 0.150 Example 3 ↑ ↑ 3 0.8 ◯ X 1.250.333 Example 3 ↑ ↑ 3 0.8 ◯ X 2.5 0.667 Comparative ↑ ↑ 1 0.2 X — — —Example 1 Comparative ↑ ↑ 1 0.2 X — — — Example 2 Example 4 ↑ ↑ 1 0.2 ◯◯ 0.5 0.100 Example 4 ↑ ↑ 1.5 0.4 ⊚ ⊚ 0.25 0.067 Example 5 ↑ ↑ 1 0.2 X —0.5 0.100 Example 5 ↑ ↑ 1 0.2 X — 0.5 0.100 Example 5 ↑ ↑ 1 0.2 ◯ ◯ 0.50.100 Example 5 ↑ ↑ 1 0.2 ◯ ◯ 0.5 0.100 Example 6 ↑ ↑ 1 0.2 ◯ ◯ 0.50.100 Example 6 ↑ ↑ 1 0.2 ◯ ◯ 0.5 0.100 Example 6 ↑ ↑ 1 0.2 ◯ ◯ 0.50.100 Example 6 ↑ ↑ 1 0.2 ◯ ◯ 0.5 0.100

Example 2

Other than changing a thickness of the adhesive layer 28 in a range of0.01 to 1.0 μm as shown in Table 1, the internal electrode layer 12 aand the blank pattern layer 24 were bonded with (transferred to) thesurface of the green sheet 10 a in the same way as in the example 1. Atest of transferability as conducted in the same way as in the example 1and existence of delamination was observed, and the results are shown inTable 1.

As shown in Table 1, in the case of an adhesive layer having a thicknessof preferably 0.02 to 0.3 μm and more preferably 0.1 to 0.2 μm, it wasconfirmed that the transferability was improved and delamination was notobserved.

Example 3

As shown in Table 1, other than changing an average particle diameter ofthe dielectric particles included in the green sheet and a thickness ofthe adhesive layer, the internal electrode layer 12 a and the blankpattern layer 24 were bonded with (transferred to) the surface of thegreen sheet 10 a in the same way as in the example 1. A test oftransferability as conducted in the same way as in the example 1 andexistence of delamination was observed. The results are shown in Table1.

As shown in Table 1, it was confirmed that by forming an adhesive layerhaving a thinner thickness than the average particle diameter of thedielectric particles included in the green sheet, delamination was notobserved. Also, in terms of eliminating delamination, it was confirmedto be preferable that the thickness of the adhesive layer is ⅕ (0.2) ofa thickness of the green sheet or thinner when the green sheet thicknessis 3 μm or thinner.

Comparative Example 1

Other than not forming the adhesive layer 28, the internal electrodelayer 12 a and the blank pattern layer 24 were bonded with (transferredto) the surface of the green sheet 10 a in the same way as in theexample 1.

Transferring was not attained at all and 20 same samples came unstuck.

Comparative Example 2

Other than not forming the adhesive layer 28 and changing the pressingforce to 10 MPa and the temperature to 120° C. at the time of bonding(transferring) the internal electrode layer 12 a and the blank patternlayer 24 with a surface of the green sheet 10 a, the internal electrodelayer 12 a and the blank pattern layer 24 were bonded with (transferredto) the surface of the green sheet 10 a in the same way as in theexample 1.

Results of evaluating transferability in the same way as in the example1 are shown in Table 1. When the adhesive layer is not formed, thepressing force and heating temperature become high and it was confirmedthat the green sheet was broken.

Example 4

After forming the multilayer unit U1 shown in FIG. 4C, other thanstacking 5 of the unit U1 and pressing in a mold, a multilayer block wasobtained in the same way as in the examples 1 to 3. A test oftransferability was conducted on 20 of same samples in the same way asin the example 1 and existence of delamination was observed. The resultsare shown in Table 1.

In the case of stacking a plurality of the multilayer units U1 in a moldto form a multilayer block, it was also confirmed that the same resultcan be obtained.

Example 5

As shown in Table 1, other than using an acrylic resin as a binder ofthe adhesive layer paste, using bis(2-hetylhexyl) phthalate DOP or(benzylbutyl phthalate) BBP as the plasticizer, and changing a kind ofthe binder of the green sheet paste, a test of transferability wasconducted and existence of delamination was observed in the same way asin the example 1. The results are shown in Table 1.

When the adhesive layer includes substantially the same organic polymermaterial as that of a binder included in the green sheet, it wasconfirmed that the transferability improved and occurrence ofdelamination decreased.

Example 6

As shown in Table 1, other than using (benzylbutyl phthalate) BBP,(dioctyl adipate) DOA, (butylphthaloylbutyl glycolate) BPBG or (tributylphosphate) TBP as a plasticizer included in the adhesive layer paste, atest of transferability was conducted and existence of delamination wasobserved in the same way as in the example 1. The results are shown inTable 1.

It was confirmed preferable that the plasticizer included in theadhesive layer paste was at least one of phthalate ester, glycol andadipic acid.

Example 7

As shown in Table 2, other than making an antistatic agent contained by10 PHR in the adhesive layer paste, a test of transferability wasconducted and existence of delamination was observed in the same way asin the example 1. The results are shown in Table 2. Note that 10 PHR ofthe antistatic agent is a part by weight of the antistatic agent whenthe adhesive layer binder (PUB) is 100 parts by weight.

As shown in Table 2, it was confirmed that when the antistatic agentcontained in the adhesive layer paste was an imidazoline basedsurfactant, the transferability improved and delamination was notobserved. Since antistatic agents other than imidazoline based ones hadpoor compatibility with the adhesive layer binder (PVB) and the adhesivelayer was not able to be produced uniformly, so that the adhesive forceremarkably declined. TABLE 2 Adhesive Layer Common Material Green SheetPlasticizer Powder Adhesive Binder Adding Particle Adding Layer AddingQuantity Antistatic Diameter Quantity Thickness Quantity No. Binder Kind(PHR) agent (μm) (PHR) (μm) Kind (PHP) Example 7 PVB DOP 50 ImidazolineNone None 0.1 PVB 6 based 10PHR Example 7 ↑ ↑ ↑ PEG400 ↑ ↑ 0.1 ↑ ↑ 10PHRExample 7 ↑ ↑ ↑ Glycerin ↑ ↑ 0.1 ↑ ↑ 10PHR Example 8 ↑ ↑ ↑ Imidazoline0.05 10 0.2 ↑ ↑ based 10PHR Example 8 ↑ ↑ ↑ ↑ 0.1 10 0.2 ↑ ↑ Example 8 ↑↑ ↑ ↑ 0.2 10 0.2 ↑ ↑ Example 8 ↑ ↑ ↑ ↑ 0.3 10 0.2 ↑ ↑ Example 9 ↑ ↑ ↑ ↑0.1 20 0.2 ↑ ↑ Example 9 ↑ ↑ ↑ ↑ 0.1 40 0.2 ↑ ↑ Example 9 ↑ ↑ ↑ ↑ 0.1 500.2 ↑ ↑ Adhesive Green Sheet Layer/ Adhesive Plasticizer DielectricDielectric Layer/ Adding Sheet Particle Particle Sheet QuantityThickness Diameter Transfer- Delam- Diameter Thickness No. Kind (PHR)(μm) (μm) ability ination (1 or thinner) (0.2 or thinner) Example 7 DOP50 1 0.2 ◯ ◯ 0.5 0.100 Example 7 ↑ ↑ 1 0.2 X — 0.5 0.100 Example 7 ↑ ↑ 10.2 X — 0.5 0.100 Example 8 ↑ ↑ 1 0.2 ◯ ◯ 1 0.200 Example 8 ↑ ↑ 1 0.2 ◯◯ 1 0.200 Example 8 ↑ ↑ 1 0.2 ◯ ◯ 1 0.200 Example 8 ↑ ↑ 1 0.2 X — 10.200 Example 9 ↑ ↑ 1 0.2 ◯ ◯ 1 0.200 Example 9 ↑ ↑ 1 0.2 X — 1 0.200Example 9 ↑ ↑ 1 0.2 X — 1 0.200

Example 8

As shown in Table 2, other than making an antistatic agent contained by10 PHR and dielectric particles (common material powder) of 0.05 to 0.3μm by 10 PHR and changing the adhesive layer thickness to 0.2 μm, a testof transferability was conducted and existence of delamination wasobserved in the same way as in the example 1. The results are shown inTable 2. Note that the PHR of the common material powder is a part byweight based on the same reference as that of the PHR of the antistaticagent.

It was confirmed to be preferable that the adhesive layer paste includeddielectric particles and the dielectric particles had an averageparticle diameter of being equivalent to or smaller than that of thedielectric particles included in the green sheet paste.

Example 9

As shown in Table 2, other than making dielectric particles (commonmaterial powder) of 0.1 μm by 20 to 50 PHR and changing the adhesivelayer thickness to 0.2 μm, a test of transferability was conducted andexistence of delamination was observed in the same way as in theexample 1. The results are shown in Table 2.

It was confirmed that an adding quantity of the common material powderwas preferably 30 PHR or smaller. Also, it was confirmed that a weightbased adding ratio of the dielectric particles included in the adhesivelayer paste was preferably lower than that of the dielectric particlesincluded in the green sheet paste. Note that an adding quantity of thedielectric particles included in the green sheet paste was 1667 PHR.

Example 10

Other than stacking 50 of the multilayer units U1 shown in FIG. 4C andpressing in a mold, a multilayer block was obtained in the same way asin the examples 1 to 3. After that, 8 of the multilayer block having 50layers were stacked via adhesive layers 28 of 0.1 μm, the external layergreen sheets 40 (refer to FIG. 8) were stacked on upper and lowersurfaces thereof in the stacking direction, and final pressing wasperformed, so that a multilayer body, wherein 400 of the multilayerunits U1 were stacked, was obtained. A ratio of the case where the greensheet was not broken was 60 to 95% (o).

1. A production method of a multilayer electronic device, comprising thesteps of: pressing an electrode layer against a surface of a green sheetto bond said electrode layer with the surface of said green sheet;stacking the green sheets bonded with said electrode layer to form agreen chip; and firing said green chip; wherein before pressing saidelectrode layer against the surface of said green sheet, an adhesivelayer having a thickness of 0.02 to 0.3 μm is formed on a surface ofsaid electrode layer or a surface of said green sheet.
 2. A productionmethod of a multilayer electronic device, comprising the steps of:pressing an electrode layer against a surface of a green sheet to bondsaid electrode layer with the surface of said green sheet; stacking thegreen sheets bonded with said electrode layer to form a green chip; andfiring said green chip; wherein before pressing said electrode layeragainst the surface of said green sheet, an adhesive layer having athinner thickness than an average particle diameter of dielectricparticles included in said green sheet is formed on a surface saidelectrode layer or a surface of said green sheet.
 3. The productionmethod of a multilayer electronic device as set forth in claim 1,wherein a thickness of said green sheet is 3 μm or thinner, and athickness of said adhesive layer is ⅕ of the thickness of said greensheet or thinner.
 4. The production method of a multilayer electronicdevice as set forth in claim 1, wherein said green sheet includesdielectric particles containing barium titanate as its main component,and an average particle diameter of said dielectric particles is 0.4 μmor smaller.
 5. The production method of a multilayer electronic deviceas set forth in claim 4, wherein said green sheet includes an acrylicresin and/or a butyral based resin as a binder.
 6. The production methodof a multilayer electronic device as set forth in claim 1, wherein saidadhesive layer includes substantially the same organic polymer materialas that in a binder included in said green sheet.
 7. The productionmethod of a multilayer electronic device as set forth in claim 6,wherein said adhesive layer includes a plasticizer, the plasticizer isat least one of phthalate ester, glycol, adipic acid and phosphoricester, and a weight based adding quantity of said plasticizer is notlarger than that of said organic polymer material.
 8. The productionmethod of a multilayer electronic device as set forth in claim 6,wherein said adhesive layer includes an antistatic agent, the antistaticagent is an imidazoline based surfactant, and a weight based addingquantity of said antistatic agent is not larger than that of saidorganic polymer material.
 9. The production method of a multilayerelectronic device as set forth in claim 1, wherein said adhesive layerincludes dielectric particles, and the dielectric particles have anaverage particle diameter equivalent to or smaller than that ofdielectric particles included in said green sheet and has substantiallythe same kind of dielectric composition as that included in said greensheet.
 10. The production method of a multilayer electronic device asset forth in claim 9, wherein a weight based adding ratio of dielectricparticles included in said adhesive layer is lower than that ofdielectric particles included in said green sheet.
 11. The productionmethod of a multilayer electronic device as set forth in claim 1,wherein: processing of bonding said electrode layer with a surface ofsaid green sheet and bonding another green sheet with a surface of saidgreen sheet formed with the electrode layer is repeatedly performed toform a multilayer block, wherein a plurality of said green sheets arestacked via said electrode layers; and a plurality of said multilayerblocks are stacked via said adhesive layers to form said green chip. 12.A production method of a multilayer electronic device, comprising thesteps of: repeating processing of bonding an electrode layer with asurface of a green sheet without using an adhesive layer and bondinganother green sheet with a surface of said green sheet formed with theelectrode layer to form a multilayer block, wherein a plurality of saidgreen sheets are stacked via said electrode layers; stacking a pluralityof said multilayer blocks via said adhesive layers of 0.02 to 0.3 μm toform said green chip; and firing the green chip.
 13. The productionmethod of a multilayer electronic device as set forth in claim 1,wherein said adhesive layer is formed by a transfer method.
 14. Theproduction method of a multilayer electronic device as set forth inclaim 13, wherein said adhesive layer is formed on a surface of asupporting sheet in a releasable way first and pressed against a surfaceof said green sheet or a surface of said electrode layer to betransferred.
 15. The production method of a multilayer electronic deviceas set forth in claim 1, wherein said electrode layer is formed to be apredetermined pattern on a surface of a supporting sheet via a releaselayer, a surface of the release layer not formed with said electrodelayer is formed with a blank pattern layer having substantially the samethickness as that of said electrode layer, and said blank pattern layeris composed of substantially the same material as that of said greensheet.
 16. The production method of a multilayer electronic device asset forth in claim 15, wherein said release layer includes substantiallythe same dielectric as that composing said green sheet.